Instrument for determining measurements.



No.'662,977. Patented Dec. 4, I900.

' C. F. SCHMELZ.

INSTRUMENT FOR DETERMINING MEASUREMENTS.

(Application filed July 5, 1899.1

2 Sheets- Sheet 1.

(No Model.)

Inventor.-

C'lzarles FJv/zmelz, fly inb' flflorwey minqswew THE "cams PETERS co.PuoTo-LITNQ, WASHINGTON, a c.

No. 662,977. Patented Dec. 4, I900.

c. F. sclmeLz.

INSTRUMENT FOR DETERMINING MEASUREMENTS. (Application filed, July 6,1899.)

(No Model.) 2 Sheets--Sheet 2.

Inventor @arleJlhS'cbnzeJz,

m: NORRIS vzrzn s co. vncroumo. WASNINGYUN o c.

ANITED STATES PATENT ()FFICE.

CHARLES F. SCHMELZ, OF HARTFORD, CONNECTICUT, ASSIGNOR OF ONE HALF TOFRANCIS H. RICHARDS, OF SAME PLACE.

INSTRUMENT FOR DETERMINING MEASUREMENTS.

SPECIFICATION forming part of Letters Patent No. 662,977, dated December4, 1900;

Application filed July 5, 1899. Serial No. 722,800- (No model.)

To all whom it may concern: I

Be it known that I, CHARLES F. SoHMELz, a citizen of the United States,residing in Hartford, in the county of Hartford and State ofConnecticut, have invented certain new and useful Improvements inInstruments for Determining Measurements, of which the following is aspecification.

This invention relates to instruments for determining measurements, andhas for one object the provision of a device which may be advantageouslyemployed by engineers and artisans in general for the purpose ofdetermining distances and angles or the trigonometrical functions ofgeometrical figures without rendering it necessary to make a graphiclay-out of the same or to make mathematical calculations with the aid ofthe usual tables provided for that purpose.

' Another object of my invention is to so arrange the instrument thatartisans and mechanics may be enabled to adj net the sameproportionately to different distances, as will hereinafter appear, thusproviding a convenient and practical tool which will be useful in manyways and which may be manufactured in various styles, according to there quirements of the user.

In the drawings, Figure 1 represents the instrument partially opened.Fig. 2 is an edge View of the same. Fig. 3 is a section on line 3 3,Fig. 1, and Figs. 4 to 6, inclusive, are diagrams illustrating themanner in which the instrument is employed for determining thetrigonometrical functions of a triangle.

Similar characters designate like parts in all the figures of thedrawings.

As above stated, the principal object of my invention is the provisionof a tool for determining trigonometrical functions, the application ofwhich to the mechanic arts is very extensive, but the theory of which isunderstood to a comparatively small extent by the very people who makethe most practical use of the same. For this reason the engineer ordraftsrnan has to be depended upon to supply figures and dimensionswhich are really the absolute results of mathematical calculations basedupon predetermined angles or diszero-point of the graduations thereof.

tanceselements which will permit of only one certain result for any oneunknown function. The average workman is not sufficiently familiar withtrigonometry, geometry, and algebra to be able to make mathematicalcalculations of the sides of a triangle relatively to the oppositeangles, or vice versa, and for this reason the instrument forming thesubject of my invention is so constructed that every element or functionof any triangle may be read at a glance and without any figuring orcalculating whatsoever. To this end the instrument in its simplest formconsists of three bars 10, 11, and 12, which for the sake of convenienceare graduated with units to form scales. The scales l0 and 11 are shownhinged or pivoted one on the other by a pivotpin 13, the axis of whichis located exactly on line with both the edges 10 and 11 of the scales10 and 11, respectively, and forms the Aprotractor 14 is secured to oneof said sca1esin the present instance to the one designated by thenumeral lland has its center coincident with the axis of the pivot-pin13, so that the angular deflection between the edges 10 and 1l may beproperly read or determined, the zero-mark of the protractor being inalinement with or formed by the edge 11. T hp third scale (designated by12) is pivotally held on the scale 10 and turns on a pivot or axislocated on a line with the edge 10' thereof, and a protractor 15, havingits zero-mark on line with the edge 10, is provided for determining theangle of deflection between said scales 10 and 12, While the graduationof the scale 12 is indexed as having the zero-mark on the pivot-axis.

In Figs. 4 t0 6, inclusive, of the drawings are shown diagrams of theinstrument as set for determining various trigonometrical functions, thedistance between the pivot-points of the scales being fixed at onehundred units and being equal to the radius 'r of a circle, the centerof which forms one point of a triangle to be calculated.

Fig. 4 illustrates one manner of arranging the instrument fordetermining the natural sine of the angle a, representing thirty dejto'retain said bent portion 16 in sliding conthe angle 3 will of coursebe 180(Ct+90):" 1S O(120)=60. The instrumentis therefore adapted toengage the said edge.

grces, sdesignating the required distance, the formula being sin. a szr.As the anglemis ninety degrees and inasmuch as'the angle a has beenfixed upon as being thirty degrees,

set with the angle yzfiO", the graduations of the scales showing sin.(4:50 (on scale 12) and cosin. (1:86 (on scale 11).

In Fig. 5 is illustrated the manner of obtaining the tangent t of theangle a, which, for example, may be fixed at thirty degrees. The formulais tang. 64:25: T. r being one hundred units, i will be found to read57.

In Fig. 6 the secant is designated bysiand the angle a is fixed atthirty degrees. The formula is sec. a :s 75:1". 1 being one hundredunits, t will be found to read 115.

It will of course be understood that when the distances are given theinstrument may be equally well employed for determining the anglescorresponding therewith, and it will also be understood that the severalsides and angles of a triangle may be readily determined, even if suchtriangle should not have a right angle for one of its elements.

It is the aim of this invention to incorporate the principles of thetrigonometrical functions above mentioned in a tool adapted for use byartisans and mechanics generally, and for this reason the scale 12 ispivoted in the manner described on a slide 16 to permit of an adjustmentof the distance between the pivots to correspond with the work in hand.

In the drawings the protractor 15 forms a part of the slide 16, and theparts are preferab'ly made of sheet metal. The slide is bent to a shapeto fit around the scale 10, the axis of the scale 12 being so locatedthat it will always be in alinernent with the edge 10 of said scale 10and the bent portion 16 being A spring 17 is carried by the slide 16 andplaced withi a space 18 provided therefor, and it serves tact with theedge 10 and frictionally to hold said slide in its adjusted position.

The preferred construct-ion of the pivotjoint of the scale on the slide16 is clearly illustrated in Fig. 3, the scale 12 being provided with ametal butt 19, similar to that of an ordinary rule-joint, which isjournaled on a stud 20, the base of which is enlarged, as at 21, toserve as a collar for retaining the stud in proper position on the butt,while the portion of the-stud at one side of the base 21 may be rivetedwithin the plate 16 of said slide or otherwise secured thereto, and ascrew 22 and washer 23 serve for holding the parts in position. By thisconstruction the parts may be held in the desired frictional engagement,the screw 22 serving as a ready means for regulating the pressurecontact, so that the scale 12 will be retained in any position to whichit may be set.

The purposes for which a tool of this character is advantageouslyadapted are manifold, the following illustrating an instance in which acarpenter is enabled to determine without calculation the requiredmeasurements. Let it be supposed that a carpenter is instructed to builda roof-frame for a house sixty-nine feet wide and that the pitch of theroof shall'be thirty degrees and forty-seven degrees, respectively. Thenthe tool will be adjusted as in Fig; l of the drawings and he will beenabled to read at a glance what lengthsthe rafters must have to conformto these conditions-via, thirty-five and threefourths feet on the steeppitch and fifty-one feet'on the other. If the lumber should be somewhatshort, he may set the tool until the lengths indicated by the scalesagree with the measurements of the stock, and he will thus be enabled toread on the protractors what the respective pitches will be and saw thejoints correspondingly. If he wishes to know what the length of aperpendicular stud under the ridge-pole must be, the scale 12 will beswung around its pivot until the ninety-degree mark on the protractor 15is on a line with the edge 12 and the slide 16 is then moved toward theleft bodily until the edge 12 intersects the point 51 of the scale 11,when he can read the required distance on the scale 12, the instrumentthus representing the framing in miniature.

In the instances just enumerated each of the scale-units has beenconsidered as representing one foot in actual practice; but it will beunderstood that the units may be representatives of any othermeasurement.

As will be observed, the slide 16, carrying protractor 15, may be movedalong the straight-edge 10 until said protractor 15 overlaps theprotractor l4, and the latter, being pivoted to the straight-edge, maybe adjusted over the protractor 15, thus providing-an ad ditional meansfor making calculations and obtaining measurements. Both protractors aregraduated, and as one may be swungover the other when the parts are inthe positions just described the desired result may be accomplished.Furthermore, the parts may be packed in this manner in a compact formfor transportation.

Many changes may be made in the 001181111110- tion and assemblage of theseveral elements constituting my improved instrument illustrated withoutdeparting from the scope of my invention-as, for instance, in some casesit may not be considered essential to have the bar upon which one of thescales is slidably mounted made in the form of a scale, in which case,however, the other two bars should be scales in drder to adapt theinstrument to the purposes for which it is intended.

The term scale as employed herein does not imply that the bars mustnecessarily have graduations thereon. The graduations are put on thebars for the sake of convenience and to avoid the necessity of employinga separate rule or scale for the purpose of measuring and setting 01fthe distances between the operative points.

Having thus described my invention, I claim- 1. Aninstrument fordetermining measure ments consisting of a grad uated straightedge; ascale pivoted directly to said straight.- edge and carrying aprotractor, the pivot of said scale being on a line With one edge of thestraight-edge and With the opposing edge of the scale; a third scale; aprotractor having a slide bent to fit around the straight-edge, to whichprotractor the third scale is directly pivoted, the pivot being on aline with the 0pposing edges of the straight-edge and said third scale;and a spring for frictionally retaining the protractor-slide upon thestraightedge.

2. In an instrument for determining measurements, the combination, witha pair of scales one constituting a straight-edge, of a third scale; asheet-metal protractor having an integral slide bent to fit around oneof said scales; and a spring carried in the channel of the protractonslide and serving to retain the same in frictional engagement with oneof said scales.

3. In an instrument of the class described, the combination, with agraduated straightedge consisting of a solid integral body, of a scaleconnected to one end of said straightedge by a rule-joint, the axis ofsaid joint being on a line with the edge of the straightedge and withthe edge of said scale; a third scale; a sheet-metal protractor havingan integral slide bent to fit around the straightedge and to which saidthird scale is pivoted with its axis on a line with the edges of saidthird scale and said straight edge; and a spring located in the channelof the slide and bearing against the back of the straight-edge andadapted frictionally to hold the slide in engagement therewith.

CHARLES F. SGHMELZ.

Witnesses:

HENRY BIssELL, GEO. H. HOFFMAN.

